A LCD is a device which controls optical transmissivity by using liquid crystal molecules so as to display images. The LCD includes two opposite substrates, and a liquid crystal layer consisting of thousands upon thousands liquid crystal molecules is sealed between the two opposite substrates. Since the liquid crystal molecules themselves can not emit light, lamps are configured as light sources on two sides of the liquid crystal display panel in the LCD, and backlight module and reflector are configured on the back of the liquid crystal display panel. The backlight module can emit light to provide a uniform backlight source. The light emitted enters the liquid crystal layer after passing through a first substrate of the two opposite substrates. The liquid crystal display panel includes a plurality of scanning lines and a plurality of data lines, the intersection of any two adjacent scanning lines and two adjacent data lines forming one pixel region, thereby the intersection of the plurality of scanning lines and the plurality of data lines forming the plurality of pixel regions. A plurality of transparent electrodes arranged in matrix are disposed on one side of the first substrate, which is close to the liquid crystal layer, i.e. the plurality of transparent electrodes are arranged in parallel along a row direction and a column direction. Optical activity states of the liquid crystal molecules can be changed by changing voltage on the transparent electrodes, so that the liquid crystal molecules function as a plurality of small light valves. Control circuits and driving circuits are disposed at the periphery of the liquid crystal display panel and can make the transparent electrodes form an electric field. The liquid crystal molecules are twisted under the action of the electric field, and thus the light entering the liquid crystal layer is refracted regularly and then displayed on the liquid crystal display panel after being filtered by a second substrate of the two opposite substrates.
In recent years, along with the development of the liquid crystal display technologies, the liquid crystal display panel becomes larger and larger in size, and is developed to a multi-person-use direction, e.g. a wide viewing angle TV technology. Hence, it is required that a viewing angle presented by the liquid crystal display panel is as large as possible. In the field of the liquid crystal display, conventional wide viewing angle technologies mainly include a Multi-Domain Vertical Alignment (MVA) mode, a Patterned Vertical Alignment (PVA) mode, an In-Plane Switching (IPS) mode, a Continuous Pinwheel Alignment (CPA) mode and the like. The liquid crystal display technology is described by taking the VA technology (including the MVA and the PVA) as an example.
FIGS. 1a and 1b are respectively a plan schematic view of a VA structure of a conventional liquid crystal display panel and a sectional view along an A-A′ direction. The conventional liquid crystal display panel includes a Thin Film Transistor (TFT) array substrate 10, a Color Filter (CF) substrate 20 which are opposite (respectively correspond to an upper substrate and a lower substrate), and a liquid crystal layer 30 sealed between the two substrates. FIG. 1a shows the VA structure of only one pixel region formed by the intersection of two adjacent scanning lines and two adjacent data lines. The two adjacent scanning lines are respectively represented as Gn and Gn+1, and the two adjacent data lines are respectively represented as Dm and Dm+1. In the pixel region shown in FIG. 1a, a pixel electrode on the lower substrate 10 is divided into a first sub-pixel electrode 1301 and a second sub-pixel electrode 1302, and there is a slit 11 between the first sub-pixel electrode 1301 and the second sub-pixel electrode 1302. There are bumps 21 on an opposite electrode 23 of the upper substrate 20, and locations of the bumps 21 respectively correspond to the first sub-pixel electrode 1301 and the second sub-pixel electrode 1302. The bumps 21 and the slit 11 can make the liquid crystal molecules at a static state (i.e. an off state) stand with a tilt of a certain angle rather than stand vertically (i.e. the long axis of the liquid crystal molecule is vertical to the upper and lower substrates). In other words, the liquid crystal molecules have a pre-tilt angle at the off state. As shown in FIG. 1b, by using this VA structure, the liquid crystal molecules can rapidly change to be horizontal (i.e. the long axis of the liquid crystal molecule is parallel with the upper and lower substrates) when voltages are respectively applied to the upper and lower substrates, so that backlight can pass more rapidly, and thus the response time of the liquid crystal molecules is shortened greatly. In addition, since the bumps or the slits change alignment directions of the liquid crystal molecules, much wider viewing angle can be obtained.
In the conventional VA technologies, it is necessary to add a masking technology in a manufacture process of the CF substrate, so as to form the bumps or the slits, which increases the complexity of the manufacture process of the liquid crystal display panel, and decreases the yield of products. Moreover, since the liquid crystal molecules at the bumps are vertical to the surface of the bumps, light leakage can not be avoided when the liquid crystal display panel is on a dark state, thereby influencing the contrast ratio. In addition, in the conventional VA technologies, since the bumps or the slits disposed on the opposite electrode of the upper substrate is not completely optical transmissive, this VA structure results in that a valid transmission region in one pixel region is decreased, which makes the penetrability of the liquid crystal display panel short and further reduces luminance of the liquid crystal display panel. The above limitations are required to be solved urgently in the liquid crystal display field.